linux-hardened/Documentation/fault-injection/provoke-crashes.txt
Simon Kagstrom 0347af4ee3 lkdtm: add debugfs access and loosen KPROBE ties
Add adds a debugfs interface and additional failure modes to LKDTM to
provide similar functionality to the provoke-crash driver submitted here:

  http://lwn.net/Articles/371208/

Crashes can now be induced either through module parameters (as before)
or through the debugfs interface as in provoke-crash.

The patch also provides a new "direct" interface, where KPROBES are not
used, i.e., the crash is invoked directly upon write to the debugfs
file. When built without KPROBES configured, only this mode is available.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Cc: M. Mohan Kumar <mohan@in.ibm.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:32 -08:00

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The lkdtm module provides an interface to crash or injure the kernel at
predefined crashpoints to evaluate the reliability of crash dumps obtained
using different dumping solutions. The module uses KPROBEs to instrument
crashing points, but can also crash the kernel directly without KRPOBE
support.
You can provide the way either through module arguments when inserting
the module, or through a debugfs interface.
Usage: insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<>
[cpoint_count={>0}]
recur_count : Recursion level for the stack overflow test. Default is 10.
cpoint_name : Crash point where the kernel is to be crashed. It can be
one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY,
FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD,
IDE_CORE_CP, DIRECT
cpoint_type : Indicates the action to be taken on hitting the crash point.
It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW,
CORRUPT_STACK, UNALIGNED_LOAD_STORE_WRITE, OVERWRITE_ALLOCATION,
WRITE_AFTER_FREE,
cpoint_count : Indicates the number of times the crash point is to be hit
to trigger an action. The default is 10.
You can also induce failures by mounting debugfs and writing the type to
<mountpoint>/provoke-crash/<crashpoint>. E.g.,
mount -t debugfs debugfs /mnt
echo EXCEPTION > /mnt/provoke-crash/INT_HARDWARE_ENTRY
A special file is `DIRECT' which will induce the crash directly without
KPROBE instrumentation. This mode is the only one available when the module
is built on a kernel without KPROBEs support.